(1) Field of the Invention
The present application relates to a vehicle body structure suitable for use in two-door automobiles.
(2) Description of the Related Art
FIG. 11 is a schematic diagram showing a rear part of a conventional two-door vehicle body. As shown in FIG. 11, at the lower part of the vehicle body 100, side members 101 extend in the longitudinal direction of the vehicle body on both sides of the vehicle body. Each side member 101 has a step-like difference in level in the vicinity of a position at which a rear tire W is disposed, in order to avoid interference with suspension components (not illustrated). Thus, as shown in FIG. 11, the side member 101 is bent at bend portions 101a and 101b. 
Here, a cross member 102 extending in the widthwise direction of the vehicle body is provided at a position where a suspension of the vehicle is disposed, and this cross member extends between the side members on both sides at the rear of the vehicle body. This cross member 102 improves the rigidity of the vehicle body against an input from the suspension.
Further, as shown in FIG. 11, the cross member 102 is connected with a rear pillar (C pillar) 105 of the vehicle body via a reinforcement 104. Here, the reinforcement 104 is disposed along the rear pillar 105, and a closed cross section is formed by a combination of the rear pillar 105 and the reinforcement 104.
The lower end of the reinforcement 104 is lengthened to be connected with the cross member 102, thereby providing the vehicle body with further improved rigidity. Note that reference character 106 in FIG. 11 denotes the center pillar of the vehicle.
In addition to the above prior art, Japanese Patent Application Laid-Open No. HEI 11-291947 discloses an art in which a wheel house of a vehicle body is connected with the rear pillar of the vehicle by means of a first reinforcement, and in which the first reinforcement is connected with the center pillar of the vehicle by means of a second reinforcement.
There are technologies in which vehicle bodies are deformed to absorb impact energy caused in a collision. However, at the time of a collision from behind a vehicle, protecting a fuel tank is a high priority, and thus there is a demand for an art for absorbing (or converting) impact energy without deforming the vehicle body. To realize this, deformation of the vehicle body should be considerably suppressed.
However, in the art as shown in FIG. 11, since the side member 101 has a step-like level difference thereof, the side member 101 tends to be deformed, at the time of a collision from behind, in the direction indicated by the arrow in FIG. 11 with the bend portions 101a and 101b as base points, so that the side member 101 could be greatly deformed in such a manner as shown by dotted lines in FIG. 11.
In addition, in the above-described art, since the reinforcement 104 is provided for the purpose of ensuring rigidity of the vehicle body, it does not contribute much to the improvement of the strength of the vehicle body. Thus, it is not easy for the above-described reinforcement 104 to suppress a considerable deformation caused when a large load is applied in a collision from behind the vehicle.
When the reinforcement 104 is used to suppress the vehicle body deformation, there is a problem that the effect of deformation suppression greatly depends on a positional relationship between the rear pillar and the cross member. For example, in a case where a positional relationship between the rear pillar and the cross member is such as that shown in FIG. 11, the reinforcement 104 is capable of enduring an input from the lower direction in FIG. 11, but incapable of enduring an input from behind the vehicle (an input from the right in FIG. 11), so that it is impossible to suppress the deformation of the vehicle body.
Further, in the art disclosed in the above-mentioned patent application, the load caused at the time of a collision from behind the vehicle is transferred to the rear pillar via the first reinforcement, and is also transferred to the center pillar via the second reinforcement. In this art, the first reinforcement is approximately vertically connected with the rearward part of the wheel house from above. Thus, when load is input from behind (at the time of a collision from behind the vehicle), it is impossible to sufficiently suppress the forward deformation of the wheel house.
That is, at the time of a collision from behind, the load is transferred to the first reinforcement, which is approximately orthogonal to the load input direction, and then is transferred to the second reinforcement, which extends in the longitudinal direction of the vehicle body, whereby the load is transferred to the rear pillar and the center pillar via the first reinforcement and the second reinforcement, respectively.
However, as already described, the first reinforcement is connected to the rear wheel house, and the connection direction is orthogonal to the load input direction. Thus, moment, not compressive load, is input to the first reinforcement, so that it is impossible to suppress the deformation of the vehicle body.
With the foregoing problems in view, it is an object of the present invention to provide a vehicle body structure in which the strength of the rearward part of the vehicle body is improved so that the deformation of the vehicle body at the time of a collision from behind the vehicle is reliably suppressed.